The EES exposes ACR management event notifications of one or more UEs to an EAS. EES also uses ACR management event notifications to inform the EAS of the need to start an ACT or cancel a previously started ACT. ACR management event notifications exposed by the EES may rely on the NEF northbound API for monitoring event of user plane path management event.
This capability exposed by the EES supports:
"User plane path change". This event supports to detect user plane path change for the application traffic and report the corresponding notification with user plane path change to the EAS.
"ACR monitoring". This event supports to detect user plane path change for the application traffic, discover the T-EAS(s), and report the corresponding notification with the discovered T-EAS(s).
"ACR facilitation". This event supports to detect user plane path change for the application traffic, make the decision for ACR, discover the T-EAS(s), influence the traffic for the selected T-EAS and report the corresponding notification with the selected T-EAS.
"ACT start/stop". This event informs the EAS the need to start or stop an ACT towards or from another EAS for a particular UE. The "ACT start" can also inform the EAS of the ACR parameters.
"ACR Selection". This event informs the EAS about the selected ACR scenario list for each AC using the EAS.
The availability of the ACR management event notifications relying on the user plane path management event notification service exposed by 5GC may change due to UE mobility between 5GC and EPC. If an EES exposes ACR event notifications to EAS(s) for a UE by relying on the 3GPP Core Network northbound API for user plane path management notifications, the EES monitors the availability of the northbound API for UE(s) served by the EAS (e.g. by utilizing Nnef_APISupportCapability as described in TS 23.502) and provides the availability information to the EAS accordingly. If CAPIF is supported, the EES determines if the ACR management event API is available and able to be exposed to the EAS for a UE via the Availability of service APIs event notifications provided by the CAPIF core function as defined in TS 23.222.
The EAS sends ACR management event subscribe request (e.g. tracking the UE's user plane path change continuously). The EAS shall include UE Identifier or UE Group ID for "user plane path change", "ACR monitoring" and "ACR facilitation" events.
The EAS may include the "user plane path change" event to indicate the EES to notify the EAS when the EES detects there is a user plane path change for the application traffic and the EAS may include Subscription Type (Early and/or Late notification defined in clause 5.6.7 of TS 23.501) and/or Indication of EAS Acknowledgement in the event subscription.
The EAS may include the "ACR monitoring" event to indicate the EES to notify the EAS when the EES detects there is a need for the ACR (e.g. when T-EAS is available at the target DNAI). The EAS may also include the Event Filters to specify the conditions to match for notifying the event, e.g., inter-EDN mobility, intra-EDN mobility.
The EAS may include the "ACR facilitation" event to request the EES to make the decision for ACR, discover the T-EAS(s), influence the traffic for the selected T-EAS and notify the S-EAS of the selected T-EAS. If required, the EAS can add an indication to request service continuity planning.
The EAS may include the "ACT start/stop" event to indicate the EES to notify the EAS of the need for start or stop ACT to or from another EAS for a particular UE. The EES may also use "ACT start" event to notify the EAS of the ACR parameters.
The EAS may include the "ACR Selection" event to indicate the EES to notify the EAS of the selected ACR scenario list applicable to ACs using the EAS.
The EES checks if the EAS is authorized for this operation.
If authorized, and if the subscription in step 1 includes at least one of the "user plane path change", "ACR monitoring" and "ACR facilitation" events, the EES may invoke the PFD management procedure with the 3GPP Core Network as described in TS 23.682 and TS 23.502 with an application id. The traffic filter information sent by the EAS is used in requesting PFD management service. Further the EES provides the same application id for requesting user plane path management event service.
If the subscription in step 1 includes at least one of the "user plane path change", "ACR monitoring" and "ACR facilitation" events, the EES checks if there exists a subscription with the 3GPP core network for the user plane path management event notifications corresponding to the UE information obtained in step 1 as described in TS 23.501 and TS 23.502, which may be triggered by other EAS for the same UE. The EES checks the availability of the user plane path management event service for the UE(s).
if a subscription with 3GPP core network does not exist, then the EES subscribes with the 3GPP core network (PCF, NEF or SCEF+NEF) for the user plane path management event notifications of the UE(s) as described in TS 23.501 and TS 23.502 If the EAS provides Subscription Type and/or Indication of EAS Acknowledgement, the EES include the type of subscription and/or the indication of "AF acknowledgement to be expected" as information on AF subscription to corresponding SMF events within the AF Request;
if a subscription with 3GPP core network exists, then the EES uses the locally cached user plane path management event notification information of the UE(s) to respond to the EAS.
The EES stores the subscription related to the EAS.
If the event is "user plane path change", the EES may subscribe to UE expected behaviour analytics (UE mobility and UE communication) for the group of UEs as described in TS 23.288.
If EAS is authorized, the EES responds with ACR management event subscribe response. If EAS is not authorized, the EES provides a rejection response with cause information.
If the target UE(s) and the 3GPP network support mobility between 5GC and EPC, the EES monitors the availability of the user plane path management event notification from the 3GPP network by utilizing Nnef_APISupportCapability or Availability of service APIs event notifications provided by the CAPIF core function.
The EES detects the ACR management event of a UE (e.g. receiving User plane path management event notification for a UE from the 3GPP core network) , or receiving ACR request from the EEC, or when the selected ACR scenario list for a particular AC changes.
If "user plane path change" Event is subscribed, the EES may cache the detected User plane path management event notification locally with timestamp as the latest information of the UE(s) and start the notification aggregation for a group of UEs. The EES decides whether to aggregate and the aggregation period based on the analytics result received from the 3GPP Core Network, local policy and User Plane path management subscription information received from the EAS. The EES determines to notify the user plane path management event notification information (e.g., DNAI) to the EASs which has subscribed for the "user plane path management" event.
If "ACR monitoring" Event is subscribed, based on the detected user plane path change report sent from the 3GPP core network, the EES checks whether the target DNAI is in the EAS profile of the subscribing EAS, if not it further checks whether a T-EAS is available at the target DNAI as described in steps 2-4 of clause 8.8.3.2. If a T-EAS is available, the EES notifies the EAS with T-EAS endpoint; otherwise this event notification will not be sent. Also, when the EES receives the ACR request from the EEC, the EES decides to send the notification to the EAS.
If "ACR facilitation" Event is subscribed, based on the detected user plane path change report sent from the 3GPP core network, the EES checks whether the target DNAI is in the EAS profile of the subscribing EAS, if not it further checks whether a T-EAS is available at the target DNAI as described in steps 2-4 of clause 8.8.3.2. If a T-EAS is available, the EES selects the T-EAS from the discovered EAS list and applies the AF traffic influence with the N6 routing information of the selected T-EAS in the 3GPP Core Network. The EES also notifies the S-EAS with the selected T-EAS endpoint.
If "ACT start/stop" event is subscribed, during the ACR launch if the EEC indicates the need to notify the EAS in the ACR request as described in clause 8.8.3.4, the EES shall send notification to the EAS to inform it about the need to start or stop the ACT to or from another EAS. The EES may include a service continuity planning indication so that the EES will monitor UE location. The notification message includes ACR identity (ACID, UE ID, S-EAS endpoint and T-EAS endpoint).
If "ACR Selection" event is subscribed, the EES shall send notification to the EAS to update the selected ACR scenario list applicable for a particular AC (ACID, UE ID) if an update was received as described in clause 8.15.2.2.
The EES sends ACR management event notification to the EAS. The EES includes the ACR management event notification information of the UE(s) and optionally the timestamp. If the event triggering the notification is DNAI change, the timestamp can be included to indicate the age of the user plane path management event notification information. The EES may only provide part of information included in the user plane path management event notification from 3GPP network (e.g. target DNAI). If the EAS had provided "Indication of EAS acknowledgement", the EES waits for acknowledgement from the EAS before it sends AF acknowledgement to the 3GPP core network.
If the event is "ACT start/stop", the notification shall include the endpoint address of the other EAS and the UE ID. The "ACT start" notification may include ACR parameters as per clause 8.8.3.9. Upon receiving the notification about the start of the ACR execution with "ACT start" event, the S-EAS avoids triggering a second ACR execution for the same identity (ACID, UE ID, S-EAS endpoint and T-EAS endpoint) until the current ACR execution is completed.
If the event is "ACR Selection", the notification shall include the selected ACR scenario list, ACID and UE ID. Upon receiving the notification, the EAS determines if it should perform ACR detection and/or ACR decision for a particular AC (ACID, UE ID).
If the EAS had included Indication of EAS Acknowledgement within ACR management event subscribe request described in clause 8.6.3.2.1, the EAS sends EAS Acknowledgement as a response to ACR management event notification to the EES either immediately or after the required ACT is completed. The EAS may reply in negative, e.g., the EAS may determine not to perform ACR. Then, the EES sends the AF acknowledgement to the 3GPP core network.
If the EAS had included Indication of EAS acknowledgement for service continuity planning within ACR management event subscribe request described in clause 8.6.3.2.1, the EAS sends EAS Acknowledgement as a response to ACR management event notification for service continuity planning of which detailed procedure is described in step 4 of clause 8.8.3.9.
The EAS sends ACR management event subscription update request to update an existing subscription. The subscription update request may include Event ID, Event Filter, Event Report, Subscription Type (Early and/or Late notification defined in clause 5.6.7 of TS 23.501) and/or Indication of EAS Acknowledgement.
The EES checks if the EAS is authorized for the operation.
If authorized and if the subscription in step 1 includes only "ACT start/stop" event, the EES stores the updated subscription related to the EAS and step 3 is skipped.
If authorized, and if the subscription in step 1 includes at least one of the "user plane path change", "ACR monitoring" and "ACR facilitation" events, the EES checks if there exists a subscription with the 3GPP core network for the user plane path management event notifications corresponding to the updated information obtained in step 1 as described in TS 23.501 and TS 23.502, which may be triggered by other EAS for the same UE.
if a subscription with 3GPP core network does not exist corresponding to the updated information, then the EES subscribes with the 3GPP core network (PCF, NEF or SCEF+NEF) for the user plane path management event notifications of the UE(s) as described in TS 23.501 and TS 23.502 If the EAS provides Subscription Type and/or Indication of EAS Acknowledgement, the EES includes the type of subscription and/or the indication of "AF acknowledgement to be expected" as information on AF subscription to corresponding SMF events within the AF Request;
if a subscription with 3GPP core network exists corresponding to the updated information, then the EES uses the locally cached user plane path management event notification information of the UE(s) to respond to the EAS.
The EES stores the updated subscription related to the EAS.
The EES checks if another EAS requires to track the UE's user plane path change or not. If not, the EES unsubscribes the user plane path management event notifications from the 3GPP core network for the corresponding UE.
The EES checks if the EAS is authorized for the operation. If authorized, the EES removes the subscription related to the EAS and sends ACR management event unsubscribe response to the EAS.
The identifier of the UE (i.e. GPSI or identity token).
UE Group ID (NOTE 1)
O
Identifies a group of UEs as defined in clause 7.2.7.
Event ID(s)
M
Event ID:
user plane path change
ACR monitoring
ACR facilitation
ACT start/stop
ACR selection
Indication of service continuity planning (NOTE 3)
O
Indicates that whether the service continuity planning is required i.e. whether EES shall monitor UE entering the predicted location.
Traffic filter information
O
The traffic filter information includes IP flow description, domain description (domain name, applicable protocol and matching criteria) or URI.
Applicable for the "user plane path change" event, the "ACR monitoring" event and "ACR facilitation" event.
Event Report (NOTE 2)
O
Event Reporting Information as specified in TS 23.502
Notification Target Address
M
Notification Target Address of the EAS where the notification is to be sent by the EES
Type of subscription
O
Indicates Early and/or Late notification to inform if the notification needs to be received before and/or after UP path configuration. Applicable for the "user plane path change" event.
Indication of EAS acknowledgement
O
This IE indicates the EES to include indication of "AF acknowledgement to be expected" within the AF request for subscribing UP path management events to 3GPP network and that the EAS will provide an acknowledgement as a response for the notifications of UP path management events to the EES. Applicable for the "user plane path change" event.
Indication of EAS acknowledgement for service continuity planning
O
This IE indicates that the EAS will provide an acknowledgement as a response to the notification of ACR management notification related to service continuity planning.
Set of characteristics to determine required EAS as detailed in Table 8.5.3.2-2.
Applicable for the "ACR monitoring" event and "ACR facilitation" event.
NOTE 1:
Either UE ID or UE Group ID shall be provided if the Event ID(s) includes any of the "user plane path change", "ACR monitoring" and "ACR facilitation" events. UE ID or UE Group ID are not applicable to "ACT start/stop" and "ACR selection" event.
NOTE 2:
This IE shall be present if the Event ID(s) includes any of the "user plane path change", "ACR monitoring" and "ACR facilitation" events. This IE is not applicable to "ACT start/stop" and "ACR selection" event.
NOTE 3:
This IE is applicable for "ACR monitoring", "ACR facilitation".
Indicates that the subscription request was successful.
> Subscription ID
M
Subscription identifier corresponding to the subscription.
> Expiration time
O
Indicates the expiration time of the subscription. To maintain an active subscription, a subscription update is required before the expiration time.
If the Expiration time IE is not included, it indicates that the subscription never expires.
Failure response (NOTE)
O
Indicates that the subscription request failed.
> Cause
O
Indicates the cause of subscription request failure
The T-EAS endpoint shall be included for the "ACR monitoring" event and "ACR facilitation" event.
In case of "ACT start/stop" event, the endpoint address of the EAS to or from which the ACT is needed to start/stop.
> Indication of service continuity planning
O
Indicating EES will monitor UE entering the predicted location.
> Selected ACR scenario list (NOTE 2)
O
The list of ACR scenarios.
> EAS bundle list (NOTE 2)
O
The EAS bundle list.
>> EAS ID (NOTE 4)
M
EAS ID in a bundle.
>> DNAIs and service area of the EAS
O
c
For the EAS ID in a bundle, it includes the DNAIs and/or service area, as described in "EAS Geographical Service Area" IE, "EAS Topological Service Area" IE and "List of EAS DNAI(s)" IE of Table 8.2.4-1.
> ACR parameters (NOTE 3)
O
ACR parameters.
>> Prediction expiration time
O
The estimated time the UE may reach the Predicted/Expected UE location or EAS service area at the latest.
UEID
O
The identifier of the UE.
ACID
O
The identifier of the AC.
NOTE 1:
This IE shall be present if the Event ID(s) includes any of the "user plane path change", "ACR monitoring" and "ACR facilitation" events. This IE is not applicable to "ACT start/stop" and "ACR Selection" events.
NOTE 2:
This IE shall be present only in case of "ACR Selection" event.
NOTE 3:
This IE is applicable only when the ACT start event notification is used to send ACR parameters to the T-EAS as per clause 8.8.3.9.
NOTE 4:
Main EAS ID in a bundle does not need to be included.
Event Reporting Information as specified in TS 23.502
Type of subscription (NOTE)
O
Indicates Early and/or Late notification to inform if the notification needs to be received before and/or after UP path configuration.
Indication of EAS acknowledgement (NOTE)
O
This IE indicates the EES to include indication of "AF acknowledgement to be expected" within the AF request for subscribing UP path management events to 3GPP network and that the EAS will provide an acknowledgement as a response for the notifications of UP path management events to the EES.
Set of characteristics to determine required EAS as detailed in Table 8.5.3.2-2.
Applicable for the "ACR monitoring" event and "ACR facilitation" event.
NOTE 1:
At least one of these IEs shall be present in the message.
Indicates that the subscription update request was successful.
> Expiration time (NOTE 1)
O
Indicates the expiration time of the updated subscription. To maintain an active subscription, a subscription update is required before the expiration time.
Failure response (NOTE 2)
O
Indicates that the subscription update request failed.
> Cause
O
Indicates the cause of subscription update request failure
NOTE 1:
If the Expiry time IE is not included, it indicates that the subscription never expires.